


Sinfell

by fellSans



Category: Underfell - Fandom, Undertale
Genre: BDSM, Bondage, F/M, Fontcest, M/M, Masochism, Masturbation, Orgasm Denial, Personal version of Sans, Punishment, Riding, Sadism, Sounding, Violence, cum, dildo, dub-con, ecto-vagina?, ectomagic dick, fantasies, flowerfrick, human!skeletons, kustard - Freeform, sub, voyeur
Language: English
Status: In-Progress
Published: 2016-06-24
Updated: 2018-04-29
Packaged: 2018-07-17 22:43:44
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 8
Words: 9,447
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7289026
Author URL: https://archiveofourown.org/users/fellSans/pseuds/fellSans
Summary: <blockquote class="userstuff">
              <p>Redo! Underfell Sans in his many iterations has wants and desires of his own from the human to anything else that might happen to titillate his senses.</p>
            </blockquote>





	1. Chapter 1

            It was just a simple brush of her fingertips lightly against his bones; soft skin catching ever so lightly against the smooth calcium and magic comprising the skeletal structure of his clavicle. She didn’t see it but he shuddered though he was sure she felt it, the twitch of his bones against her fingertips. Fell wasn’t like this much with her but...he started seeing her differently, the way her hips swayed lightly with each step she took when she was happy or the way her voice made the back of his skull tingle with a feeling he wasn’t as much used to. He’s desired women before just mostly for a one night stand to get his rocks off when he was in the mood but this, no, she filled him with a desire worse than anything and there was nothing much he could do about it but suffer quietly or go jack off when she wasn’t here. With her living in the house, the time he had to jack off was slim to none. But that touch on his clavicle, it still left little electric pings zinging through him. Fell groaned and scrubbed a hand over his face, now was not the time to have a raging hard-on but there it was, threatening to bust out of the elastic holding his shorts up. Despite him having that fucking boner he had to keep it under control lest she see it and cause all sorts of problems. He had no idea how she felt on the matter and felt super fucking embarrassed to ask whenever he thought about maybe bringing up the subject. Didn’t really matter what he tried to think about he strayed to those slender hands grasping his bones and caressing him all over made him shudder again; fell swore under his breath and waited till she was out of the door. It was shopping day for her but he didn't know if she left yet or had gone outside to sit; usually he helped her out at the store but with the shit he had to do which right now was quickly deal with how damn horny he was she was shit out of luck. Fell watched with hungry eyes at her backside before the door shut behind her. Shit he was in a mood...

            Fell teleported to his room knowing full well the door was partially open, he didn’t really care all too much as he chucked his shorts into his growing sock pile; his slippers he left by the door. He leaned against the wall near his swirling trash tornado and sat there for a few seconds breaths heavy while he attempted to will himself back to some form of normal but his trailing thoughts really didn’t do much to stay libido pulsing his magic through his bones. Fell thunked his head back against the wall and closed his eye sockets, grasping the length of his magic flaring up through his hip-bones. He pulled up, hard and heavy, once and held and then again, and again. Slow and deliberate, denying himself the speed and quick gratification he really wanted. It burned slow much like a candle as he stroked up and down, up and down. Every now and then he had to bite back the small delicious noises threatening to spill from him in case she came back into the house: he didn’t want her to know what he was doing. Fell’s thumb brushed against his tip, he imagined her slender fingers dancing along his length, teasing the magic member, tracing lines and dips and dots, circling his sensitive spots to tease him; his own fingers mirroring what he thought she would do. It was both hell and ecstasy, the push and pull of winding tensions within him and the ever thrumming desires to pull so hard, so fast he might rip the magic right from him. The sound of the front door closing made him stop for a second or two, his magic pulsing in steady hard beats. As he tried to make sure she didn’t hear him, Fell’s breaths came in heavy gasping sounds, his free hand rushed up to his skull to try and block out some of the sounds coming from him but it only managed to make some of the breath come out in slight whistling tones as it rushed past  his bones. Once he was sure she wasn’t coming upstairs again he continued, slower than before, his hand almost a complete stop as his thumb trailing designs on his tip did most of the work.

            Pre-cum dripped down him in thick beads, his bones rattled slightly as one of the only louder whimpers of his escaped his means of keeping quiet. He heard her shift downstairs and bit down on his radius; _bad idea._ The sting of his teeth scraping against his bone caused a thick shudder to wrack his body and another sort of whining moan to escape from his skull. He wouldn’t be able to keep going at this pace for long, his self-control starting to falter, Fell removed his arm from his mouth and let it hang limp against his thigh while he finally sped up, his hand rhythmically pumping over himself. Fell’s jaw slightly hung slack as his breaths finally became nothing more than short pants and the occasional whimper, he called her name once, quietly in a stuttering voice as he yet again pictured her hand working him over while he sat there unable to do anything but moan and pant in a pleasure induced trance. This time he bit down on his finger and worked harder, jerking his length again with force enough to rip it off if it were anything but magic. Her name tumbled like a waterfall from his mouth, short soft bursts muffled by the bone in his mouth and he didn’t realize that she’d silently moved up the stairs upon hearing her name. She stopped outside of his door and he didn’t even hear her as she slid to the floor herself. Over and over again, her name moaned in succession becoming more erratic to match his ever quickening pace. He knew he was nearing the end, so very close to cumming in his hand. Not knowing she sat there transfixed watching him and with reckless abandon carried on until with strong bursts he came through the bones in his hand getting red sticky cum on his floor and bones crying out in his moment of orgasm. Quietly, she moved from the door while Fell sat there panting.


	2. Abuse

**Summary for the Chapter:**

> Punishments? Papyrus is all about that but Fell on the other hand really enjoys the searing pain brought on by it.

**Notes for the Chapter:**

> This is Fontcest so if you don't enjoy Fontcest don't read it. Also dub-con and violence so yea there's that. If ya don't like either don't read! :D

            Fell hissed and burbled out a sharp cry of pain. The sting of the whip digging into his bones radiated pain through his body and he arched his bare spine back against Papyrus who stood over him with a harsh expression down-turning his features into a livid scowl. Drool leaked from his mouth not just because he couldn’t help himself but because part of his jaw sat shattered in its housing. With another crack of the whip he cried out again with tears streaming down his face. He dug his shaking phalanges into his palms and attempted to stay his hips from absently rocking against the end of the platform his brother had him tied to. Yes he was broken, yes he was bleeding the very marrow from his bones but Fell didn’t care, he needed stimulation of some sort or another or he’d go even crazier than he already was. Unfortunately for the smaller skeleton nakedly tied to a rough wooden slab this was nothing more than a punishment, Papyrus saw fit to teach Fell a lesson and well, there wasn’t much he could do to fight against the person who was more than capable of killing him instantly. He dragged in a horrendously shaky breath and bit back an absolutely disgusting moan from sneaking its way out of him, Papyrus didn’t know how bad it was, how much he craved the pain and if his brother ever found out there’d be no way he’d ever leave this room.

            With his long legs Papyrus somewhat bent over and placed his heeled boot onto Fell’s skull and ground into the wood spitting words of fire at him, pathetic, weak, stupid... every insult in the book degrading the lanky skeleton shot out in rapid succession with each grind of his boot. Fell already started crying silently from the pain wracking his body but he craved a touch from Papyrus, something, anything to alleviate the magical pressure building around his hips. He whimpered and strained to reach the backboard with his hipbones, weakly struggling against the overly-tight bonds around his wrists ankles and spine. The whip cracked again accompanied by a degrading scolding from its holder; a rib finally shattered and fell from its holding. Fell screamed in a broken tone and Papyrus bent down to speak something to Fell while his hand reached down and roughly started jerking up and down the lower half of the skeleton’s exposed spine. This time Fell couldn’t help but moan out shakily and listened as his brother told him just how disgusting he was. Did he care? No, Fell didn’t care as pleasure welled around him to the point where he jerked himself as best as possible to his brother’s rough, painful motions. Fell, so alit with need felt already close to the edge of an orgasm made these little tiny pitiful noises but Papyrus didn’t want to hear it, he let go of his brother’s spine and grasped his head instead, roughly lifting it up and slamming it back down onto the platform; it shut Fell up enough to whimper out from the swimming sensations now fogging his mind.

             Papyrus, with his disgusted scowl loosened the bonds around Fell’s ankles, hoisting Fell’s hips up as he straddled the skeleton enough so he could shove his dick inside his brother’s hip cavity. He dropped his tight pants enough that his bright red cock glowed free and hard against himself before he did as pleased and shoved the cock into the empty space roughly scraping the magic appendage against the sacrum. Fell bucked against him but Papyrus pulled back, slapping the back of his skull harshly; he stilled, after all this was about Papyrus teaching Fell a lesson, not getting the other skeleton off. The taller skeleton roughly pushed a fast pace as he jerked his cock into Fell, rapid harsh thrusts that left Fell choking back tiny sobs from how they wracked his already pained body with spasms; Papyrus kept going. The only noises from Papyrus were grunts and the occasional huffs and panting noises, he kept Fell’s skull roughly pushed against the platform. Fell felt about ready to burst, the fast paced stimulation driving him to a high state where he simultaneously felt ready to pass out from the pain and about ready to fall while he hovered over everything. Soon enough Fell felt his brother’s burning hot cum rush through his bones; another slutty pathetic whimper slipped from Fell as Papyrus removed himself from inside Fell and cleaned himself up. The taller skeleton turned heel after his magic dissipated and he adjusted himself and walked back up the stairs from the room leaving Fell sobbing and jerking around on the table wanting more.


	3. I wanna get fucked.

**Summary for the Chapter:**

> Fell sometimes just wants to get fucked into oblivion, is that so bad?

            It wasn’t something the kid would understand, Frisk. She wouldn’t get it, the quiet smaller human who Fell had grown quiet attached to. No, she wouldn’t understand the fact that sometimes Fell just wanted to get fucked. Sometimes he just wanted to ride a fucking dick like a horse and scream out like a bitch boy and pretend he was just a little slut who enjoyed being fucked. He couldn’t tell her, she wouldn’t understand and he couldn’t do that to her although the idea of her fucking him with a strap-on really riled him up good. So just as he kept his attraction to her to himself he made sure no one, not even his boss knew about this little kink of his.

            Fell was in his room sitting half naked on the floor with a rather thick ribbed, hard plastic dildo suctioned to the wooden slats comprising his bedroom floor. It was a bright purple in color and looked too large for anyone in their right mind to fit in any orifice, except for maybe a skeleton with enough space in his pelvis to accommodate nearly anything he wanted to shove up there. He panted, denying himself from fucking himself on the phallic object stuck to the floor. He wanted it bad but keeping himself horny and wanting made the orgasm at the end even stronger if he prolonged the inevitable. Thankfully no one was home besides him to hear the small and pitiful whines that slipped past his teeth as he ground his bare hips in the air, desperately wanting to stuff himself on that plastic cock. He trembled and clutched and unclutched his hands into balls every so often, really testing his will-power that seemed to diminish with each passing second.

 _“i want...”_ He whispered, staring at the floor. The dildo was positioned behind him so he couldn’t see it but as he scooted along, he backed up into it and nearly cried out. Fell bit down hard on his left first finger, teeth digging into the bone with a sharp pain that made him whine again like a bitch in heat. His soul glowed a near dazzling bright color that shone through the loose material of his t-shirt. He rubbed the back of his pelvis up against the dildo, once again denying the fucking he so wanted. In the back of his head, the owner of the dick asked him what he wanted, Fell responded with a desire filled. _“i want your cock.”_ The person in his mind dragged Fell’s pelvis up and almost involuntarily Fell lifted his rear up into the air. _“i-i’m a good lil fuck-toy aren’t i?”_ He asked, whimpering at the lack of stimulation in any way. Fuck did he want it bad. The man in his mind gave him a nod; Fell plunged himself onto the dildo, the hard ribs scraping against the bones of his pelvis.  He cried out as he sat there, magic gathering around the dildo to form a pseudo hole for the dildo to fuck. His cock raged on hard and tall and Fell couldn’t take it anymore.

 

            The ‘Fell skeleton cried out like a bitch and began riding the dildo hard and fast, bouncing on the large object with abandon. His mind was gone and all that he could really think about was stuffing himself full to the brink of breaking himself. A simpering and quite disgustingly lust-filled moan loudly echoed around Fell’s room as he kept bouncing on the plastic dildo. He imagined it all as some stranger who just wanted him as a fuck toy, a monster who was good for his holes and nothing else and Fell couldn’t help himself from jerking harder on it. Fell kept his door wide open just in case anyone did decide to come home, they’d hear him and probably see him if they went upstairs but that didn’t really mean the worst for Fell he enjoyed the humiliation of people seeing him act like a little bitch getting fucked. He tilted his head back and let loose another whimpering moan, fingers digging into the wood hard enough to scratch the surface. It all made such delicious sounds, a slippery suctioned noise of the large dildo ramming into him and the slight scrape of it on his pelvis and it drove Fell mad.

 

            Fell couldn’t stop, it hurt to keep himself feeling so full but he didn’t care, he enjoyed it, it felt so good getting stuffed so bad; drool leaked out of the corner of his mouth but again, he didn’t care. He was a little bitch right now and most certainly acted like it. Whispers of things his fucker would say to him, _take my cock you slut_ or look at you getting _fucked like a bitch_ tumbled from him between the sickening noises coming from him. If he were riding anyone outside of a dildo right now he’d beg them to fuck him harder. He’d force himself to bounce harder on their cock and feel like they were ripping him apart, he’d want them to break him and so that’s what he tried to do on his own.

 

            He wasn’t going to last very long at this rate and Fell wanted the torture of continuously getting fucked for a good hour or two so he summoned a tendril of magic and wound it around his own cock, squeezing it at the base to keep him from cumming and then shoved the rest down his dick hole, doubly making sure he didn’t cum; again he cried out. His dick, glowing and pulsing in a transparent red color the same as the pseudo flesh surrounding the dildo twitched more than a few times. Fell, as he jerked himself on the dildo jerked the tendril of magic in and out of his dick telling himself in his voice of a stranger _“you like getting your dick fucked to don’t you you little bitch”._ Another moan tumbled from him. Nonsensical words, phrases and noises tumbled from the sex crazed skeleton. He was so close to an orgasm, he could feel it from all the stimulation but he didn’t allow it to happen. He wanted that denial, he just wanted to keep riding that cock stuck to his floor for as long as he possibly could but it wasn’t long before his bones started shaking again.

 

            Fell let go of his dick and a whole mess of pre-cum leaked out all over him, he didn’t care. The horny skeleton continued to fuck the dildo until in a mess of cum and nearly crying he came while he continued to fuck himself into oblivion on the floor. Overstimulation poured into all of his senses but he wasn’t going to stop, he wanted to keep going until all he could think about was that cock he was fucking and at this rate it wasn’t going to take long. Soon enough the front door opened and both the human and Papyrus got home, Fell didn’t care and moaned in a wet babble of noise unable to stop his lust-driven madness as his brother marched up the stairs to see what was going on. If his brother had to fuck him into submission again to get him to stop, he’d be ok with that too just so long as he could keep getting fucked like the fucking piece of shit bitch he was.


	4. Revelations

**Summary for the Chapter:**

> You (Frisk) are at a bar with fell, he's singing something just for you and things go through your mind while he awakens a long sleeping desire in you.

**Notes for the Chapter:**

> This is just a small blurb of a thing that outlines some of Frisk's thoughts; it's not as mature as the others though. This was written as though you're Frisk. It's not very long and next thing I finish writing will be longer I promise.

            This was the first time you got a good look at him. It was electric. The surface was a place the three of you shared with the rest of the world, a house braced against the terrors of the underground and the violence smattered into the dirt that comprised the overworld. But this was something just for you, a song ringing in your ears, a dirty bass line that thrummed in sensual beats against your ear drums. For the first time since you left the wretched darkness your eyes opened and you stared at him. He stared at you, sockets half lidded, a flare of heat and magic leaking from his socket shining a red against the dull pale color of his skull. The grin plastered on his skull accompanied the words dripping out from between his teeth. A fluorescent light shimmered against the gold tooth giving pleasant accent to the black and red of his outfit. His phalanges gripped the microphone tightly while his baritone voice floated in a sea of gravel in the air around you. The red light comprising his only pupil stared at you, transfixed on staring straight into your soul with a sensually charged gaze; you shuddered as he swiveled his hips in time to the song. You swallowed hard as his free hand reached down from the small stage he stood on to brush against your cheek, thumb barely ghosting against the red of your lips.

            You couldn’t keep your eyes off of him. It wasn’t as if you hadn’t stared at him before, his bones were often the subjects of your dark thoughts. How it would feel with them pressed against your bare body... how his phalanges would roughly grab you and dig into your flesh. A flare of red nearly the color of the magic in his skull spread across your cheeks. The skeleton rumbled out a chuckle between sentences, carrying on with an ever present sexual undercurrent. You couldn’t tell if it was the room getting hotter or if it was you. It was mesmerizing to watch him move, his bones shift against the others under his clothing, the small crest of his hip bones peeking out from the top of his shorts, a small section of vertebrae exposed... You wanted to feel them as much as you wanted him to feel you. The way he sang, slow and wanting, it flooded you with a desire to have him slam you against his bed and fuck you rough and slow like. It wasn’t like you’d thought about it before like that; your desires hadn’t been so... mature? You hid what you wanted well from him. In a world full violence and sex you hesitated on trying to give into their rules. But now? A deep shudder ran through your body straight to your core. The skeleton finished up his song, drawing his hand down his ribs while he winked at you, beckoning you forward. You weren’t going back to your room tonight.


	5. Bodies

**Summary for the Chapter:**

> After a failed date and humans being dicks to our flower covered Frisk. Flower and Fell come home and deal with Flower's self depreciative habits and Fell makes good use of their time to tell Flower how much he loves her body and of course show her.

**Notes for the Chapter:**

> I started writing this a year ago on a long car ride home from a road trip. A friend of mine sent me a song that fit extremely too well for Flower and the idea for this sprang into my head so I began writing it in google docs on my small ass phone. I put it down after a while losing motivation to finish it but I finally got around to continuing it. 
> 
> I'm sorry if its a bit too long and drawn out in places it shouldn't be, m'still not quite adept at writing softer, slower paced pieces like this. Also the song that inspired this piece to be written is this  Ugly by: Nicole Dollangange 

            It was a slow night. Both Fell and Flower had a long day and were exhausted. Fell slumped against the couch with his head resting on the back with his eye sockets closed whereas Flower lowered herself to the floor and sat leaning against the arm rest. Heavy sighs slipped from the both of them; Flower massaged her feet and Fell was just about too dead to move. They'd just gotten home from the first date Fell’d taken Flower to since they've gotten together officially. He felt so awkward asking but it turned out to be as bad as Fell thought it might.

“You doin ok honey?” He asked, eyes still closed.

“No.” She snapped bitterly, staring at the floor between her skirt clad legs. Fell scrubbed a hand over his face and groaned heavily, this had to be the worst first date in existence. Another sigh then escaped from him and he stood up feeling like an old man with creaky joints, he bent down once he stood in front of flower and picked her up bridal style; she protested with a squeal and tried squirming out but Fell held her firm and kept her there. Flower huffed loudly in annoyance, her arms crossed tightly against her chest as Fell carried her upstairs, she could have done it herself.

“What are you doing?”

“What does it look like I'm doing?” Fell grumbled, nearly kicking his door open. Flower hummed with frustration and went to move away as Fell set her down but he held her there with a firm grasp on her shoulders. “You're gunna need help getting out of that damn dress if you don't want to rip it.” _Or your flowers…_ Another huff from Flower.

“I don't care… It's not like I’ll need it again…” Under her flowers you could tell she was rolling her eyes with all the bitterness in the world. He gripped her shoulders tighter.

“Don’t you dare fucking say that! Those assholes, they don’t know what they’re fucking talking about-“

“They obviously fucking do Fell!... I got these damn things growing on me, I’m a freak! I’m not fucking human anymore...I’m not pretty, I’m not sexy, I..I-“

Fell shook her once, jostling her out of her self-depreciative dialog. “You are not allowed to say that shit about yourself! I don’t wanna fucking hear it. You, are fucking, gorgeous.” His voice came out as a snarl, he wasn’t angry at her but at those fucking cunts at the restaurant who kept talking about Flower as they ate. It took all is self-control to keep from killing those fuckers right then and there. Flower rolled her eyes again and unzipped her dress, shaking herself from him as she walked towards her portion of the room. She shook the dress from her personage, the silken deep red material pooling at her feet; Flower kicked the material away from her, the dress getting caught in the swirling trash tornado in the process. Fell tried grasping it before it got shredded in the swirling winds but failed and watched in annoyance as the material turned to red confetti before him.

           

            He inhaled sharply through his nose holes and exhaled slowly, trying not to lose himself, Fell almost already did and he didn’t want to ruin anything else for Flower as he already did tonight. Fell scrubbed a hand over his face and watched Flower’s back as she had her arms crossed, semi-staring at her dresser with unseeing eyes. Her frame was on the smaller side, shorter than him by a few inches and slim in weight too. She had flowers poking out between her shoulder blades, some dotting her lower back above the line of her underwear and quite a lot poking around her arms, wrists and of course there was the large crown of golden blooms surrounding her head like a parasitic halo. As much as he sorely wished they were all gone and not marring her perfect body, the sight of them wasn’t unwelcome either. He loved seeing her, looking at her and knowing every inch of that person was his. Fell swallowed hard and walked towards her, she heard his heavy steps and tilted her head towards him.

“Hm?” Flower inquired with a curt tone.

“Don’t talk sweetheart.” Was his reply, short and low. She immediately turned her head back and slouched as if sulking where she stood, too irritated to pay much attention to him. Although he didn’t stop moving forward and eventually stood about a foot away from her, close enough to reach out and lightly caress his hand over her shoulder. Flower almost slapped his hand away but she was too tired to care at the moment.

“You’re beautiful, ya know that?” She gave no response. Fell leaned forward. “Everything,” his skull closed in near her ear, voice a low even rumble “from your small feet, to those hips of yours,” he reached forward and placed his hands delicately on her hips, careful not to crush the blooms. She almost jumped out of her skin but a heat flushed along it instead, cheeks tinging near the color of his magic. “The curve of your back and the shape of your lips. Your soft skin, an your supple flesh. I love your hair sweetheart, it’s chocolate color, an’ the way you’re lightin’ up like a firework as I touch ya.”

            His hands roamed over her body as he kept talking, each feather light caress and squeeze of her causing fire to blaze through her. She didn’t believe a word of it, she didn’t think she was beautiful, there was nothing about her that should be likeable, she was scarred. Marks from previous blooms, things from her surface life... she didn’t have a desirable figure, no prominent breasts or hips and her face felt too child-like and innocent to be anything Fell or anyone else would ever want and yet... Fell was there telling her how beautiful she was. He reached up to her breasts, pulling her towards him gently so that her back rested against his front. He still had on his ‘suit’ and the fabric felt a little rough against her bare skin. Flower desperately wanted to say something but it was as if her throat dried up and all she could do was exhale in a hitched manner. “It doesn’t matter, what everyone else wants in this fuckin’ world.. They may want someone with giant tits and an ass as wide as a truck but sweetheart,” Fell got in closer, the air from his words tickling her ear “I want you and no one else.”

            Flower shuddered hard, inhibitions seemingly disappearing in a tired haze of burgeoning desire and graveled voice coming from her skeleton. He bent his skull down and pressed his teeth against her exposed shoulder, nipping at the space right next to her bra strap while his hands lowered and wrapped around her in a possessive manner. Fell pulled at the strap with his teeth and dragged it down off her shoulder eliciting a slight gasp that caught in Flower’s throat.

“Tell me if ya want me to stop.” He muttered into her skin. Flower could at any point in time say no, a tiny voice in the back of her head was screaming at her to call it off, throw a shirt on and run off downstairs. _‘He’s only goin to hurt you like all the others!’_ She was tired of letting her doubts and anxieties ruin her so she shook her head and whispered “continue” to him in the voice only he could hear.

            Fell’s socket’s lowered as he unclasped her bra, reaching around with one of his hands to do so. It was simple, two clasps and a quick tearing of the strap later and it was no longer significant. He pressed his teeth against her bare shoulder blade in a kiss, his glowing tongue draping out from his mouth to taste the exposed flesh. Flower shuddered again against him, unsure of what to do in these scenarios. She wasn’t experienced like him and a quick pulse of fear ran through her; what if she failed him? With a hard swallow she tried shoving the thought aside. Fell re-grasped one of her bare breasts giving it a light squeeze while his thumb brushed against her exposed nipple; he trailed more nips up her body.

“I want to make ya feel good sweetheart.” All she could do was nod. Her body felt stiff, aching from the long day before and the near inability to relax although blooms of pure fire seared straight to her center. Flower’s never quite felt so... her lip quivered as she tried not making a sound. Fell’s other hand scraped back along her hip again, trailing a single phalange against the elastic of her waistband. He slipped it under and tugged the material down enough to expose the entirety of her hip. “Ya don’t gotta be quiet, moan for me my dear.” His voice now came from her other ear, fang like teeth nipping at her earlobe and neck, careful to avoid any of the extremely sensitive blooms. Flower couldn’t take it and she almost whined out a soft breathy tone, succumbing to his wishes.

            Red hot desire washed over the both of them. Fell wanted to take her now, stuff her full with his length and fuck her till she knew how much he loved her and Flower wanted more than just the searing touches from Fell. He pulled her silken panties down farther off of her hips, exposing her supple rear to him eliciting a hard squeeze and another breathy moan to slip from Flower’s lips. A chuckle rumbled through his chest as he detached and went about tossing the articles of clothing he wore into the pile in his corner of the room. A red glow pulsed from his soul resting under his ribs and encompassed his hips, the magic gathering into the shape of his cock. Heavy steps brought him back against her and she felt his length press up against her back, it was warm and not unlike the supple silicone from cooking ware. Flower couldn’t help but press herself harder against him.

            Fell once again grasped one of her breasts in his right hand  while his other trailed down and ran circles on the skin below her belly button.

“I need ya to open up sweetheart.” She hadn’t realized how tight she stood against herself and took a step out to the side. Fell’s hand immediately dove down and caressed her inner thigh moving inward to run a single finger along her slit. She inhale sharply through her nose and felt another wave of fire light its way into her core. Fell’s wanted this for a while but this was all about her. He parted her folds and slowly rubbed a finger along her clit, another shudder waving through her body; another deep rumble of a chuckle coming from Fell. It felt good, his bare bones pressed against her and touching her right where it felt good.

            He continued circling her, caressing her, kissing her, nipping at her. It was gentle, it was slow and it was careful, he could feel her slowly start to relax in his grasp and even though he was already hard his member strained itself against her back.

“Prepare yaself sweetheart.” The bones of his fingers were slick and soaked enough that he circled her entrance and plunged a finger in getting a near mewl of a cry from her. It was Fell’s turn to shudder now. “Ya good?” She nodded. Fell slowly moved his finger inside her, pulling it out and twisting it slowly back in. The bones scraped against her sopping flesh, it was strange but not unwelcomed in the slightest and soon enough she whispered out a “more” feeling embarrassed to ask. He obliged and slipped another one of his fingers in, speeding up just enough to make her moan again. The sounds were sinful, no one should love hearing those sounds as much as Fell did, they did something to him entirely different than anyone else’s would have.  It was the feeling of making her feel good instead of himself that drove him forward.

            “Ya like that sweetheart?” He asked in a rough, husky tone. She nodded, her hair brushing against his bare clavicles. He pushed harder, working her over enough that with most of her exhales came soft shuddery tones. Fell wanted more, he enjoyed doing this for her but his own lust filled desires were starting to cloud his thoughts. He removed his fingers from her causing her to make a small sound of protest. He brought his hand up to his face and licked his fingers clean with a sensual moan to add fuel to the fire.

            She never thought it could be like this, feeling as good as she was with someone, sharing herself with another. Flower wanted him to keep going, feel his bones inside her again but instead got something more than that. Fell pushed her legs open wider with a quick press of his knee against her leg and prodded the tip of his length against her.    
“I’ll take it slow n tell me if it don’t feel good.” His voice was barely above the whisper Flower’d been speaking in. She gave him another nod. He guided his length into her slowly, parting her lips and stretching her out with satisfying ease. Fell groaned loudly and Flower let out a small whimper, the feeling of being stretched out foreign to her. “Deep breaths sweetheart. “ He murmured into her ear, pressing his teeth against the side of her head. He let her adjust to the full feeling of him inside of her before slowly pulling himself out.

            It was an odd feeling at first and slightly uncomfortable being so stuffed but the strange feeling eventually subsided. “I-I need...”

“You need what?”

“Movement.” Her face flushed a deep red again. Fell obliged and pushed back in slowly, finding a good slow rhythm. Flower cried out this time in a louder manner than before, other women did that and she was certain Fell would like it. If she could bring him some satisfaction as well all the better; it shouldn’t be just about her, she didn’t deserve it. The pair settled into an even pace, Fell speeding up after a while of her getting used to the movement inside her.

“Shit sweetheart, ya feel so fuckin good!” She bit back on a simpering moan. Fell pushed the two of them forward and let Flower brace herself against her dresser, hands gripping the wooden surface for stability. She was glad she couldn’t see or else she’d nearly be too mortified to continue.

            Time wore on, the sounds of bones hitting against her flesh harder and harder echoed dully in the space around them. Fell had gripped onto her hips tightly, roughly digging his phalanges into her, it hurt a little but she enjoyed it. His bones scraped against her bare skin, it was a different feeling to what she thought and it was something she really enjoyed. After a long string of lust filled noises Fell spoke again.

“I love you, everything about you. There’s no way in hell you’d ever get me to think otherwise. I aint gunna fuckin let ya. Fuckin’ stars you’re so damn good!” His words were growls, near animal like tones. Flower could feel herself close to a climax, Fell’s words making her walls tighten around him.

“F-fell I-“ She cut herself off.

“S’ok sweetheart, come for me. Don’t hold back.” She didn’t. Fell reached a hand around and brushed his thumb back against her clit, circling around it in time with his thrusts. It wasn’t long before she stopped her movements and came hard against him, fluids gushing over his hips. Flower trembled in his grasp and he had to keep her up as thrust into her a little longer. She felt over stimulated but he was so close, she didn’t want to say anything and ruin it. A few moments later his stuttered movements halted as he came inside her, sticky hot cum the color of molten cherry candy dripping from inside her. He pulled out when he noticed she was near ready to collapse.

            She hadn’t experienced anything quite like that and it felt so good although she felt extremely tired and probably would fall sleep standing up if she could. However her knees felt weak and Fell had to keep her up. He pressed his teeth against her hair, murmuring praise into the strands of hair and the golden blooms. The glow of his length dissipated and he picked her up, carrying her to his bed. He said something about them both needing sleep but Flower’s mind was too fuzzy to quite understand what he was saying. She’d drifted off before the blankets were even pulled up over them.


	6. Voyeur

**Summary for the Chapter:**

> With his mind a-buzz, Fell goes to visit Sans in his room only to hear Sans jacking himself off in the most delicious of ways.

**Notes for the Chapter:**

> The two skeletons are human in this.

He walked towards Sans’ room mind buzzing like a bee and in need of some conversation to keep his head grounded. It wasn’t always Fell needed to air his thoughts considering his stunted emotional output but today was a rare occasion. His slippered feet thudded softly against the wooden floor of the upstairs; he hesitated going any further, expression a litany of varieties of anxious, nervous and frustrated. Fell had his hands shoved in his shorts pockets, white hair mussed and sticking up in places, his ruby pupil stared at the slightly ajar door. He contemplated the fate of his afternoon, whether or not to actually go through with letting his emotions out to play. He shook his head and vehemently walked forward, damning his brain to hell in the meantime. 

Sans rarely left his door open even when he wasn’t there, it was odd for Fell to see it so cocked open with a pool of soft lamp light flooding into the darker corridor. Fell wasn’t sure if he wanted to knock or just walk in but he stopped the moment he came anywhere near close to seeing inside the door. He heard it first, a soft heaving breathing resonating in the space between him and the door. The sound was irregular, rising and falling in shudders and not quite deep tones. Fell sucked in a breath and clamped a hand over his mouth. A soft whine came from the door immediately muffled by what Fell only assumed was a pillow jammed over his mouth. Those buzzing thoughts in his mind dissipated to the sounds of Sans sliding his hand along the length of his cock. 

Fell slipped down to the floor outside his room, peeking in past the door. Indeed the classic version of himself in near perfect replica give or take some differences lay on his bed slowly stroking himself. It took Fell nearly everything he had to bite back a groan. He didn’t want to move, the soft barely acknowledgeable sounds both tickling his curiosity and flooding his consciousness with heated desire. It immediately set to work achingly hardening his length. The two had fucked before, Fell topping more often than not but there was something about the privacy of the other’s solo play that stirred something in him. His soul constricted, tightening in the warmth of his desire. Another loud shuddery breath escaped the confines of Sans’ room clouding Fell’s thoughts and pulling his length that much tighter against the confines of his shorts. Gods he loved hearing those sounds.

He turned enough to stare back into Sans’ room. Sans had one hand gripped tightly around his member and the other teasing his back entrance with a finger slowly pushing and prodding. His face looked tilted back, mouth parted just enough and eye-lids just barely closed, body shuddering now and again as his thumb brushed against his tip. Sans made a simpering sound, a hum of a moan wobbling in sheer pleasure. The sound pitched into a name, his name. He heard a drawn out “fell-“ tumble unabashedly from the other’s parted lips, shaky breathing accenting the heavy implications. Once again Fell sucked in a shaky breath. 

Sans moved faster. His slow deliberate motions fervently changed. He slipped two fingers in pumping hard and fast in and out his ass while his other hand worked in a fast rhythm over his cock. Each thrust with his fingers elicited a deliciously pitched tone and it was driving Fell nuts. Those were pandering delicious noises, Sans knew Fell was there, how could he not? Magic signatures were hard to mask, especially those so intertwined as theirs were. He couldn't help it, his fingers drifted to band of his shorts, dipping under them. Fell, open palm, ghosted his hand over his member through his boxers. It wasn't much by way of friction but he had to do something or he'd go mad. Sans made another simpering moan and you could tell just how much he was enjoying Fell listening to him. It was more or less a silent acknowledgement to Fell without breaking focus or breaking the illusion of secrecy and yet... Fell did what he could to keep from being seen. That didn't stop either of them though.

His breathing was even and deep, slow breaths to keep calm. It was a stark contrast to Sans' still shuddered breaths. Fell's soul glowed a simmering red; it illuminated the creamy pale of his skin and through the white of his old t-shirt. It leaked from his left eye, smoke like and barely there yet Sans felt its magic reaching out. A soft cyan glow contrasted against the yellowed light in Sans’ room, his soul stretching itself out to reach back to Fell’s. Sans moaned unabashedly and jerked over himself harder. His breathing became even more erratic and it was more akin to a whining pant. Fell teased his thumb over his tip, biting down on his finger to keep silent. He could tell just how close Sans was to finishing by the pitch and loose tone in his voice. More of his name tumbled from Sans, shaky, needy and fully wholly wanting. Fell's eyelids slunk shut, his whole body felt a tingle of electricity prickling over him, near liquid fire in his veins. He wholly enjoyed this, listening to Sans like he was, each slick movement, each little wobble in his lusty sounds...

Sans let out a loud shaky cry, his stimulation quickly becoming too much for him to take and slowly pulled his fingers from inside himself and slowly circled his entrance. His hand quickened to a rough and stuttered pace. Fell listened to the quick huffs of air noisily filling the still atmosphere; he quietly dragged a cupped hand around his cock, waiting for Sans to finish. Sans’ tones grew needier again before they ceased altogether, he was so close. His whole body shuddered just a few quick seconds later, his back arching as he came hard between his fingers. Sans wobbled out another “fe-elll” drawn out and slow, breathy and so unbelievably sexy Fell nearly bit through two of his fingers trying to keep quiet. Silence filled the air outside of the heavy slow breaths from the two of them. Carefully, Fell got up making sure to be as quiet as he could while he slipped away back off to his own room leaving Sans laying on his bed grinning contently.


	7. Riding

**Summary for the Chapter:**

> Our lovely pair of humans, Fell and Sans are in for a night of sin; Fell helps Sans ride him for the first time.

**Notes for the Chapter:**

> Just another Kustard piece! This is one of my favourite ships outside of Frans and I can't ever get enough of it.

            Their kisses were hot and heavy; open mouthed, ghosted and yet hard. Fell lay propped against a mound of pillows in Sans’ bed and Sans ground down on top of him, leaned over and drinking as much as the other in as he physically could. Heaving breathes permeated the space between them, punctuating each kiss with pure want and desperate need. His length nearly burned in his shorts, hard and painfully so with Sans so desperately working on him. Sans had his lids half closed, blue hued pupils dimmed in the low light of his room, he had his fingers laced tightly between Fell’s with no intention of letting go. He shuddered and claimed Fell’s mouth again after a breathy moan tumbled from between his lips.

            Fell squeezed Sans’ fingers in reassurance before de-tangling them; both worked their shorts quickly off their lower halves, only now clad in old t-shirts and bare bodies; Fell still had one red slipper on.

“jus’ go slow, work yaself down onta me n then start movin aight?” Fell spoke with a soft huskiness that would charm anyone into his bed. A zip of pleasure shot down Sans’ spine.

“heh..” Breathless and nervous is how he sounded. “i’ve had you inside me before Fell.”

“yea,” he started. “butchya aint ridden anyone before. not like me.”

Sans let out a dry chuckle and once again twined his fingers with Fell’s. Fell groaned as Sans slowly slid his ass down onto his length, pushing himself down full hilt till his ass cheeks fell flush with Fell’s hips. Sans shook out a heady moan.

            The two sat on Sans’ bed for a few painfully long moments, heavy breaths the only sound between them. He felt nervous, unsure of himself yet this is what he desired. Sans wasn’t that openly sexual as Fell was and-

“c’mon baby, start movin’. you’ll get used ta how good it feels~” Fell interrupted his thoughts with rumbled words, leaning up to nip just behind his earlobe. Sans stifled a moan and started, low and slow. Even motions that pushed and pulled him on Fell’s cock. It felt blissful, Fell let go of one of Sans’ hands and tightly dug his fingertips into Sans’ plush hips and Sans gripped Fell’s arm for stability. Sweet little noises shuddered out of the more inexperienced of the two, breathy but full of delicious passion.

“a-ahhh stars fell-”

Fell’s cock shifted as he turned his hips, hitting straight against Sans’ prostate. Sans felt glorious and so did Fell; Fell bent upward to press more hot kisses to Sans’ lips.

“you’re doin’ so good baby, makin’ me feel so fuckin’ good~” Fell pressed words of praise into Sans, assuaging his nervous mood as best as an Underfeller could.

 

            Sans drank everything up, little bursts of electricity zapping him with each thrust, Fell pushed up to meet him halfway, nearly pushing in farther eliciting a louder moan from Sans. They kept going, an even rhythm as Sans rode Fell for the first time. Desire filled Fell’s belly, twisted into a hot core to make the other feel so good. He may be an asshole but sometimes when fuckin’ his lover he wanted to be the good guy. Their bodies pulsed and moved against the other, Sans bouncing needy against Fell and Fell eagerly meeting up with fervor. A low moan rumbled out from Fell only to be swallowed by his lover’s lips once again crushing into his. Sans wasn’t going to be able to take much more of this, he wasn’t a lightweight but the pure sensation of getting hit over and over again in just the right place was going to push him over the edge quicker than he wanted.

 

            He hadn’t felt this good in a long while, sex between them was always enjoyable but there was something in Fell that relished seeing someone so worked up over him like Sans was, just taking him all in and then some.  Fell could tell between the shake in each plunge down and that lingering soul tie between them Sans didn’t have a whole lot left in him. “i feel how close ya are~”

“i-i…” He began but quickly dissolved his words into a moan at a particularly rough strike against his prostate. His body shuddered, tightening around Fell with greater need. “oh g-god.”

Fell felt his soul constrict inside him, he hummed in praise and appreciation. “i don’t care if ya last any longer, ya aint gotta show off ta me, jus’ let yaself feel good, s’all i want.”

Sans offered a weak nod, lids scrunching shut to focus on the feelings alone and Fell couldn’t get enough of the pure expression of lust etched onto his face. Knowing he didn’t have much left in him, Fell let go of Sans’ other hand with a slight whimper coming from the other and grasped his length in his hand. Sans cried out and found a way to push harder, his ass slapping with hefty motions. He jerked his hand in a smooth manner over Sans’ cock that already dripped sopping wet with pre-cum. Sand near rocked his hips up into Fell’s hand with each hard bounce, desperately begging for more without having to say anything.

Fell obliged.

            Needy whimpers poured from Sans, each breath quick and panting.

“jus, a little more..”

Fell dragged his thumb with a heady chuckle around his head, trailing circles and patterns around the sensitive flesh. Sans felt it, a tug in his core and very little warning came through Fell’s hand, still riding his lover with urgency. He was nearly quiet except for those short little sounds, over stimulation of his orgasm pinging through his body. A shudder wracked through Fell’s body, he sucked in a hard breath and through his own panting breaths hummed out little noises of his own. “a-ah fuck- sans… nnnnmm- fuck… fuck!” Fell’s soul flared in his chest, a bright red hue of color tinging his skin a delicious red. He gripped back at the other side of Sans’ hip, stilling him while he was shoved up to his base inside of him. Fell came with a stuttered growl and finally Sans collapsed against him, weak in the knees. He caught the other carefully and pressed his lips to his snowy hair, rumbling words of praise and adoration into him. They stayed content like this, breathing heavy and slow until they both lazily drifted off, Sans still content to keep Fell inside him.  


	8. Lovers in the night

**Summary for the Chapter:**

> Just a sweet little missionary fuck between two lovers~

**Notes for the Chapter:**

> Something kind of romancy thing that I felt the need to write.

            Lights were soft in the bedroom. Not that they needed to be but it added an air of, closeness to the pair that really offset the dark recesses of their minds. The sheets, cotton and sturdy felt rough under them in the best of ways. Fell had Sans held up by his knees, the latter skeleton laying on his back whilst looking up at the former’s skull. An unsaid tenderness softly vibrated between the two of them, their souls near beating in tandem. Bones scraped against bones, the mattress rustled with familiar movements, slow and even rolls as Fell sunk into Sans. He inhaled, slowly exhaled a shaky breath and gripped against their sheets, Fell took this opportunity to press their ribs together and move his teeth against his lovers. Sans poked his tongue out, dragging the blue conjuration against Fell’s teeth. He parted said teeth and claimed Sans’ tongue, dragging it in and caressing it with all the passion he felt over flowing from his soul. Not all of his sex had to be rough, not all of it had to hurt him, sometimes, he wanted to give to his partner, make them feel good. Sometimes, he needed it soft and attentive.

            Sans let go of the mattress, gripping his phalanges around one of Fell’s femurs, digging the tips of his appendages into the bone. Between their kiss he whispered, _“nng, more…”_ and Fell obliged, picking up his pace with a groan. Sans’ legs tightened around Fell’s back, his other hand finding Fell’s whom laced his phalanges in between Sans’. Fell squeezed his partners hand tightly, catching a moan that threatened to spill from between his teeth. His bones felt alight each time he felt his length slipped into Sans, that little space inside his pelvis and the magic gripping onto him as if Sans’ life depended on it. Fell shuddered, rolling into him a little harder, unable to keep much of his promised softer pace; Sans cried out with a gasped tone, arching his spine with fervor. His toes wanted to curl in on themselves, tighten up with how taught his body felt. Sans’ soul thrummed with nothing but pure desire for his lover.

            Blue light spread out from his ribs and mingled with red pouring from Fell’s, a purple whirled between them as Fell adjusted the two of them, taking Sans’ legs and pressing them back against his body while Fell’s knees straddled either side of him, Fell’s length pressed in deeper and almost made Sans jerk against him. _“mmmmf, s-sweetheart, shit- you feel good.”_ Fell’s voice did nothing but rumble the words out in a low tone, whispered to the side of his skull, now it was Sans’ turn to shudder. His sockets slipped half shut as his gaze unfocused, staring somewhere between Fell’s sockets and his nose-hole, pleasure filled his senses and nothing but a passionate love filled his soul.

            A red tendril of magic slipped out from between Fell’s ribs, reaching around through Sans’ own ribs and slipped around his soul, squeezing the dripping blue object. Sans moaned in a whimpered tone, squeezing Fell’s phalanges tighter. Fell dragged his soul from its cage, humming in an appreciative manner at the soul that was equally his as it was Sans’. The two weren’t bonded yet but damn near should be, if they kept up as they did they would be. Stars Fell felt good, Sans a softer mirror of his own feelings. He couldn’t help but stare into that pleasure addled expression of Sans’, it made his own soul constrict.

              _”more.”_ Sans about whispered, he was so close as it was, sitting on the precipice of cumming against Fell’s bones. Fell took Sans’ soul into his mouth, dragging his tongue along the gooey surface. He got a nose-full of its musky scent, moaning against the heady taste against his tongue. Sans’ breath caught on a moan, wobbled and pitched and needy. _”i-i’m close.~”  
”f-fuck.. me too. aah- stars.”_ He pushed harder, thrusting into Sans with abandon while his tongue worked the soul in his mouth. Each breath Sans made sounded punctuated with a whimper. It wasn’t long before Sans suddenly arched his spine again, pushing his pelvis against Fell’s while he came ribbons of blue against Fell’s ribs; his soul constricted erratically.   _“mm, that’s good, cum for me sans.~”_  Fell continued his thrusts for maybe ten more seconds, Sans’ bones shook by the time Fell came, his own ruby colored cum filling the wrap of magic around his length. He let go of his soul and it plopped back into place; Fell pressed a long kiss against Sans’ teeth. _“shit, i love you.”_

_“heh, i love you too, stars fell.”_

            Fell rolled off of him, laying beside Sans. Sans curled around Fell, tucking himself against the other’s curves. Even if they didn’t fall asleep, they’d be comfortable laying there for a while, they could clean up later.

**Author's Note:**

> It has my Underfell Sans whom my friends and I call Fell. The 'She' is Frisk from either regular of flowerfell underfell. Sans is my boyfriend's rendition of Classic Sans.


End file.
